The present invention generally relates to articles of jewelry and, more particularly, to a method of setting a gem in such articles.
It has been proposed in the jewelry industry to mass produce articles of jewelry by casting gem supports such as rings out of metal material. Sand-casting techniques have been used and recently centrifugal-casting techniques have likewise been employed. The latter technique provides a very dense structure whose outer surface for the gem support is smooth and can therefore satisfy strict plating requirements.
Generally the proposed centrifugal-casting techniques include the formation of a plurality of preform wax models which are all arranged and interconnected on a so-called wax tree-like structure. The tree-like structure is then embedded by hardenable embedding material contained in a treatment vessel. The embedding material hardens to form a mold cavity in a burning process. Simultaneously with this hardening process the wax model is melted and removed from the mold cavity. Thereupon heated molten metal material is introduced into the mold cavity. After hardening of the metal material the embedding material is broken away, the cast gem support is ready to be set with a gem.
This known burning process takes about ten hours to complete, and about three-fourths of this time is wasted in preheating to temperatures of about 700.degree. C. subsequently the centrifugal-casting of the fluid molten metal material whose temperature is approximately 1100.degree. C. follows at about the same temperature of the treatment vessel. After a certain cooling-down period has elapsed, the treatment vessel is water-quenched to a still relatively high temperature.
The manufacture of the preform wax models is formed in resilient rubber-type molds having negative patterns whose contours are complementary to the gem support to be cast. The molds may be adapted to form gem supports having apertures or projections or relatively narrow branches as, for example, provided in chaton- or corner-type settings.
The cast gem supports are provided with holding elements such as stubs, fingers, corners or frames. A jeweler must manually place a gem in position on the cast gem support and thereupon fixedly anchor the gem in place, for example by bending a finger-type holding element over a facet of the gem.
However, this type of manual setting procedure is unsatisfactory. A great deal of skill is required for the jeweler to properly orient the gam and to subsequently anchor it in place. A great deal of time is lost in completing the jewelry article. These requirements make the total cost of manufacture relatively high. In the case of high-quality, expensive jewelry articles, a jeweler must be particularly skillful in setting the gem. Such rigid quality control means, of course, additional expenses.